Olefin is a class of industrial chemicals useful as, for example, monomers or comonomers for the synthesis of polyolefins. However, the olefin must be substantially pure when it is used for synthesizing polyolefin, especially when the polyolefin is prepared in the presence of a high activity catalyst because any appreciable concentration of impurities can be detrimental to the catalyst. One of the impurities is carbon dioxide, a well-known catalyst inhibitor.
Alumina is a well known adsorbent in many chemical processes such as the polymerization of olefins, e.g. ethylene, for the removal of water and small concentrations of methanol, carbonyl-containing compounds, and peroxides. However, the use of alumina has disadvantages that impair its effectiveness as an adsorbent. For example, alumina has a low capacity when used as an adsorbent for the removal of CO.sub.2 from an olefin fluid stream which contains CO.sub.2 at low level concentrations and alumina must be regenerated when it becomes saturated with CO.sub.2. Incurred regeneration costs over time dramatically impact the economics of its use.
Molecular sieves are frequently used as adsorbents for CO.sub.2, but are inefficient when used for the removal of CO.sub.2 from a fluid stream containing low molecular weight olefins such as ethylene.
Caustic scrubbers or bulk caustic scrubbers can also function as absorbents for CO.sub.2 from a gaseous stream but have the disadvantages of being hazardous, and subject to water attack with subsequent caking thus severely limiting their capacity. It is therefore an increasing need to develop a more efficient process which is capable of reducing the carbon dioxide concentration in a fluid which contains an olefin to such levels that the CO.sub.2 is not detrimental to catalyst activity in polymerization processes using the olefin.